Ship yards, refineries, chemical plants, power plants and other industrial facilities typically require the installation and use of temporary service lines such as temporary electrical cables, piping, hoses and the like. Often these temporary service lines are laid directly upon floor surfaces, roadways, parking lots, driveways, and other vehicle passageways. These services lines, though temporary, may remain in place once laid for an indefinite period of time. Consequently, a need exists for a portable apparatus that will allow the passage of vehicles, especially heavy vehicles, over such temporary service lines and to restrict such passage as may be necessary.